RAMSTEIN AIR BASE, Germany (CNN) -- U.S. Marine Cpl. Wassef Ali Hassoun has told medical and psychological professionals that he was abducted from his base near Fallujah, Iraq, last month, military sources said Monday.

The sources said Hassoun is talking to so-called repatriation specialists, but he has not yet offered details about how he traveled from Iraq to Lebanon, where he was recovered last week.

The sources said the matter remains under investigation.

Hassoun, a 24-year-old translator of Lebanese descent, was reported missing June 20 when he did not report for duty at his base in Iraq. He was last seen June 19 before showing up in Lebanon.

He is undergoing medical and psychological evaluation at Landstuhl Regional Medical Center in Germany.

The Marine has not yet undergone questioning by the Naval Criminal Investigative Service, which is handling the probe into his disappearance.

Sources said Hassoun may issue a statement within the next day, thanking those who helped him but offering few details about his experience.

He is said to be in good condition and has been making phone calls to friends and family. He is not in custody but is in seclusion for his personal privacy, sources said.

The Marine Corps had listed Hassoun as a deserter after he disappeared based on information from interviews and other intelligence gathered at the base.

A video -- apparently featuring Hassoun blindfolded with a sword above his head -- was broadcast June 27 on the Arabic-language TV news network Al-Jazeera. A narrator on the tape said he would be killed if the United States did not free jailed Iraqis. (Full story)

At one point, reports on Islamist Web sites said Hassoun had been beheaded.

On July 5, a group claiming to have kidnapped Hassoun said it had taken him to safety after he promised not to return to the U.S. military, Al-Jazeera reported. (Full story)

Doctor: Hassoun in good shape

Hassoun arrived Friday in Germany after leaving the U.S. Embassy in Beirut, Lebanon. He turned up at the embassy Thursday, apparently arriving the day before at a home of relatives in Tripoli, Lebanon

"I found him in excellent physical condition, and I did not see any bruises or any injuries on his person," Hassoun's attending physician, U.S. Navy Cmdr. Peter Marco, said Friday. "He's very exhausted."

Marco said Hassoun, who is 6 feet tall, had lost about 20 pounds -- dropping from 190 to about 170 -- and the Marine told him his spirits were down before his reunion with his family in Lebanon. Marco said Hassoun also reported suffering from chronic headaches.

Lt. Col. Sally Harvey, a psychologist working with Hassoun, said Monday that he was getting more sleep. "Cpl. Hassoun had been sleeping only several hours a night," Harvey said. "He is getting a considerable amount of sleep and eating well. His spirits are good and he's involved in the repatriation process."